Kids enjoy hours of creative play with these time-honored classroom favorite unit blocks. Crafted from hardwood, which is stronger than Oak, each block is finely sanded smooth to insure it will be splinter-free. All edges are beveled and corners are safely rounded. The roof boards are 1/4" hardboard. These classically designed blocks are based on the precise unit size of 2 3/4" W x 1 3/8" T x 5 1/2" L. Intermediate Set includes 170 pieces in 21 shapes. Weight 84 lbs. Additional shipping charges apply. All sets ship UPS delivery. (Photo shown with a variety of sets).